Furnace



Patented Apr. 4, 1950 FURNACE David P. Cooper, Youngstown, Ohio, assignor to The Cold Metal Products Company, Youngstown, Ohio, a corporation of Ohio Application January 23, 1947, Serial No. 723,851

1 Claim.

This invention relates to furnaces, particularly furnaces for heating material, as, for example, annealing furnaces. In certain of its aspects it has to do with furnaces of the type having an elongated material support and an elongated hood over the support, the heating or heat treatment being carried on continuously or progressively during relative movement between the material and the hood.

It has heretofore been known to dispose material to be heated on an elongated material support and move the support beneath a stationary hood of less length than the support to heat the material as it advances. In furnaces of the type used for such a procedure the elongated material support may be straight or curved; for example, it may be arcuate or even circular and the hood is of course shaped to conform to the shape of the material support but is of smaller dimension in the direction of its length than the support. The words elongated and length as herein used apply to material supports and hoods of various shapes, even circular or arcuate, the length or direction of elongation of a circular or arcuate support or hood being the direction along the arc.

For purposes of explanation and illustration the invention will be described as embodied in a heat treating furnace having a generally circular material support and an arcuate hood of less than 360 over the support. Furnaces of this general type are disclosed in copending applications Serial Nos. 497,523 (Patent No. 2,417,063) and 629,085. In the furnaces of those applications the hood or heating chamber is stationary and the material support moves therein. Such furnaces are quite satisfactory when the heat is supplied through burners in the stationary hood or heating chamber. However, difliculties arise when it is desired to supply heat more directly to the material on the support.

I have devised a furnace of the general type above referred to in which heat may be supplied directly to material on the support yet the structure is relatively simple and inexpensive and not likely to become out of order. I make the material support or hearth stationary and I provide for moving the hood over the support or hearth in the direction of its length. By this provision I facilitate the direct heating of material on the support as the heating means may extend up through the stationary support or hearth. The hood may be sealed to the support to prevent transverse egress of gases. Material enclosures may be disposed on the support and may be sealed to the support. Material in the enclosures 55 may be heated by heating means within the enclosures. The heating means may be radiant tube burner means. The heating means may be disposed at a level below the level of the material being heated and in one embodiment may consist of a series of radiant tube burners in the material enclosure beneath the material. The hood may be mounted on opposed parallel series of rollers and means may be provided for rotating at least certain of the rollers to move the hood over the support in the direction of its length; when the hood is an arcuate hood its movement in the direction of its length is, in accordance with the above definition, a turning movement about its center.

Other details, objects and advantages of the invention will become apparent as the following description of certain present preferred embodiments thereof proceeds.

In the accompanying drawings I have shown certain present preferred embodiments of the invention, in which Figure 1 is a partial transverse section through the heating chamber and hearth of an annealing furnace having a generally circular material support or hearth and an arcute hood or heating chamber of less than 360 over the hearth;

Figure 2 is a horizontal cross-sectional view taken along the line IIII of Figure 1; and

Figure 3 is a view similar to Figure 2 showing a modified structure.

Referring now more particularly to the drawings, the apparatus shown comprises a circular hearth I 0 and a heating chamber II which is arcuate or c-shaped in plan and concentric with the hearth H), the hood subtending a central angle of somewhat less than 270. Since the general type of furnace employing a circular material support and an arcuate hood is not new, and since the shape of the furnace in plan does not constitute my invention, I do not show any plan view of the furnace. In shape it is like the furnaces of the copending applications above referred to. The hood or heating chamber is composed of side walls l2 and I 3 and a roof 14 built up of refractory brick and insulation and assembled within a suitable binding. The hood is mounted on channels l5 which in turn rest upon I-beams l6, being welded thereto; and the I-beams have arcuate rails l1 fastened totheir under surfaces as by clamping or welding. There are provided two concentric series of flanged rollers l8 and I9 mounted on shafts 20 arranged radially of the furnace. The inner rail l1 rides on the rollers I8 and the outer rail l1 rides on the rollers I 9.

3 Some of the shafts 20 extend to a position cantrally of the furnace where they may be suitably driven to move the hood over the stationary hearth. The rollers II and II are keyed to those shafts which are thus driven. The rollers may be mounted for rotation upon any shafts which may not be driven, which shafts may be stationary.

The hearth I is supported on beams Ila resting on a concrete base 2|. Set upon the hearth are piers or stools 22 which carry spaced plates 23 which in the embodiment shown are circular and adapted respectively to support coils 14 of metal strip to be annealed. The purpose of the piers cr stools 22 and the plates 23 is to support the coils in position spaced above the hearth.

Each coil'is adapted to be disposed within an enclosure-or retort 2! which is of circular shape in plan. The hearth is formed with a series of circular supporting portions each surrounded by an oil seal channel 28. Each retort 25 has a hori-' zontal portion 21 resting on the edge of the circular .hearth portion and therebelow a downwardly extending portion 28 extending into the oil seal channel 29. Thus the coil in each retort is sealed to the hearth against egress of gases.

Likewise a sand seal 29 extends around the inside nected with the hood and projecting into the sand seals 29 and 30 respectively. Thus the hood is sealed to the material support by the opposed sand seals, the seals being continuously effective even during movement of the hood over the support. The sand seals prevent egress of gases transversely from within the hood.

Disposed within each retort and below the plate 23 therein are means for heating the material or coil in the retort. In Figures 1 and 2 such means are in the form of radiant tube burners 33 having inlet and outlet connections 34 extending down through the stationary hearth l0. The radiant tube burners 33 are disposed immediately below the level of the plate 23 but offset laterally from the edge of the plate whereby to provide for circulation of heat upward and around the coil. With the heating tube arrangement shown in Figures 1 and 2 a natural circulation of atmosphere within the retort may occur, the atmosphere therein passing upwardly outside the coil and downwardly through the core of the coil.

An alternative arrangement of heating means is shown in Figure 3. A series of generally parallel radiant tube burners 39 are disposed directly beneath the plateupon which the coil is mounted.

4 By this arrangement the coil is heated upwar through the plate and also by the circulating at mosphere in the retort.

The hood may move upon the rollers II and II either continuously or intermittently, and the operation of the furnace, so far as the supply of heat to the material being heat treated is concerned, may follow conventionl practice. When a retort is rendered accessible by passage of the trailing end of the hood therepast it may be opened. the heat-treated coil removed and another coil inserted and the retort closed. The heat to the burners may be regulated so that the work is subjected to a conventional cycle involving preheating, soaking, slow cooling and fast cooling.

While I have shown and described certain' present preferred embodiments of the invention, it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied within the scope of the following claim.

I claim:

A furnace comprising an elongated stationary support, a series of closed material enclosing retorts supported on and sealed to said support, said retorts being spaced from each other lengthwise of said support, means mounted on said support and extending into each of said retorts for heating material therein, an elongated hood having a top and side walls but open at its ends extending over said support and spaced from said retorts, means for moving the hood over the support in the direction of its length, and sealing means sealing the hood to the support and continuously effective even during movement of the hood over the support for preventing egress of gases transversely from within the hood.

DAVID P. COOPER.

REFERENCES CITED The. following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 325,175 Hill Aug. 25, 1885 1,305,991 Beeman June 10, 1919 1,739,958 Farmer Dec. 17, 1929 1,749,866 Winzer Mar. 11, 1930 1,903,909 Cope et al Apr. 18, 1933 2,050,029 Williams Aug. 4, 1936 2,089,843 Dilson et al. Aug. 10, 1937 2,201,308 Edge May 21, 1940 2,331,956 Schwier Feb. 18, 1941 

